Summary The Air Tindi Ltd. de Havilland DHC-3T (Turbo) Otter (registration C-FXUY, serial number142) water taxied from the Air Tindi dock at Yellowknife, Northwest Territories, for a charter flight to Blachford Lake. The aircraft was loaded with two crew members, seven passengers, and 840pounds of cargo. Before the flight, the pilot conducted a pre-flight passenger briefing, which included information about the location of life preservers and emergency exits. During the take-off run, at about 1912 mountain daylight time, the aircraft performed normally. It became airborne at about 55mph, which is lower than the normal take-off speed of 60mph. The pilot applied forward control column to counter the pitch-up tendency, but there was no response. He then trimmed the nose forward, but the aircraft continued to pitch up until it stalled at about 50feet above the water and the left wing dropped. The aircraft struck the water in the East Bay in a nose-down, 45 left bank attitude. On impact, the left wing and left float detached from the aircraft, and the aircraft came to rest on its left side. The crew was able to evacuate the passengers before the aircraft submerged, and local boaters assisted in the rescue. There were no serious injuries to the crew or passengers. The aircraft suffered substantial damage. Ce rapport est galement disponible en franais. Other Factual Information The pilot was licenced in accordance with the Canadian Aviation Regulations (CARs) at the time of the occurrence. The pilot reported for duty at 0700 mountain daylight time1 on the day of the occurrence, which was the first day of work for the pilot after a seven-day leave period. The pilot's flight duty times were within the prescribed limits. The pilot had three hours of sleep on the night preceding the occurrence. The accident flight occurred 12hours after the pilot had reported for work. Visual meteorological conditions existed at the time of the occurrence. A special weather observation recorded at the Yellowknife airport at 1919, approximately 10minutes after the occurrence, was as follows: wind 310True at 10knots; visibility 15statute miles (sm); showers in the vicinity of the airport; and few clouds at 4000feet above ground level (agl), scattered clouds at 5000feetagl, and scattered clouds at 6000feetagl. There was no weather-recording equipment at the float base. The pilot estimated that the winds were 320Magnetic2 at 12knots, gusting to 18knots. The occurrence aircraft was a de Havilland DHC-3T (Turbo) Otter, equipped with a Pratt and Whitney PT6-34A engine, serial number PCE-RB0058, and SI-3-8100 floats. It was certified to a maximum take-off weight of 9000pounds under the Supplemental Type Certificate SA03-50. The occurrence flight was preceded by a flight to Daring Lake that departed Yellowknife at 0826. While mooring at Daring Lake, the aircraft sustained damage to the left water rudder bracket. Upon returning to Yellowknife, it was determined that the rudder bracket would have to be repaired by removing the aircraft from the water and welding the bracket at Air Tindi's hangar at the Yellowknife airport. To balance the aircraft on the float cart while pulling it out of the water, weight had to be added to the rear of the aircraft to prevent it and the cart from being too front-heavy. To accomplish this, 40imperial gallons of fuel was added to the rear tank before the aircraft was towed from the water. The pilot and aircraft maintenance engineer also sat on the rear of the floats for added ballast. The task of repairing the water rudder bracket was completed at about 1800, and the pilot took off to conduct a half-hour flight to burn off the fuel in the rear tank. However, before much fuel could be burned off, the aircraft returned to the Air Tindi float base, as the passengers for the 1800flight were waiting at the dock. Upon returning to the dock, the pilot began preparations for the impending flight. Aware of the tail-heavy configuration of the aircraft, the pilot requested that 20to 30imperial gallons of fuel be loaded into the forward fuel cell, in addition to the 50imperial gallons already in the centre tank and the nearly 40imperial gallons in the rear tank. While the pilot checked in with dispatch, the ground crew finished loading the aircraft. An inexperienced dock hand, tasked with refuelling the forward fuel tank, added only 10imperial gallons to the forward tank. The cargo was split into two components: 300pounds secured in row five and the remaining 540pounds in the aft cargo bay. Passengers were loaded in the front of the aircraft in the first four rows. The pilot was aware that insufficient fuel had been loaded onto the aircraft to counter the weight imbalance. However, as the passengers had already been loaded and the flight was one hour behind schedule, the pilot did not have further fuel added to the forward fuel tank. He was aware that the aircraft was likely aft of the centre of gravity (CofG) limit, but did not complete a CofG calculation. Transport Canada has made provision for the use of standard weights for passengers where actual weights are not available.3 This facilitates the calculation of total passenger weight without going through the time-consuming process of either querying passengers about their weight or actually weighing them. Air Tindi used the standard passenger weights to calculate the total passenger weight. The published standard summer weight is 200pounds for an adult male and 165pounds for an adult female. The actual average weight for the male passengers was 230pounds. The sole female passenger was 150pounds. The actual total passenger weight was 1532pounds as opposed to the 1365pounds that was calculated using the standard passenger weight model. The aircraft's total take-off weight was 8873pounds, which was below the 9000pound maximum certified take-off weight. The aircraft performance charts indicate a CofG aft limit of 148.3inches at a weight of 8873pounds. At the time of the occurrence, the aircraft's CofG was 158.8inches aft of the datum. This was 10.5inches aft of the CofG limit. The following is from the Private Pilot Manual: The pilot and ground crew attendant escaped through the right cockpit door and assisted two passengers through this door. Water began to fill the cabin, rendering the cockpit door unsuitable for further evacuation. Two passengers escaped via the roof emergency exit. The pilot crossed over the fuselage, opened the right rear cargo doors, and assisted the remaining passengers from the aircraft. The ground crew attendant ensured that the assembled passengers remained together on the front of the right float of the aircraft. All crew and passengers were recovered by local boaters and returned to the Air Tindi dock. Fatigue can have an insidious detrimental effect on human performance. The Transport Canada publication, Crew Resource Management, states the following: "Fatigue in aviation is recognized as a serious safety concern.... Fatigued pilots are less vigilant, more willing to accept below-par performance and show signs of poor judgement."